Note: Descriptions are shown in the official language in which they were submitted.
1327~3
Apparatus 4~r the ~lanufacture
of a Pneumatic Tire
This invention relates to a method and apparatus fsr the
manufackure of a pneumatic tire and in par~icular to an
apparatus an~ a method for forming an annular unvulcanised
elastomerlc component which can be assembled to a toroidal tire
carcass D
The me~hod and apparak~ls are particularly suitable for t~le
manufacture and assembly of sidewall components to the moul~
carcasses of a radial tireO
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In conventional radial ~ire manufacture the tire carcass is
assembled on a flat drum and the sidewal~ components, a~exes,
and o~her com~onents such as cha~er~, bead reinforcements,
etc-, ar~ added in the fla~ ~tate. The carcas~ i5 thell sha~ed
up into a oroi~al confiyuration ~ri~r to ~ssembly o' the
breaker belt, tr~ad, ~nd sidewalls. The addition o~ the
sidewalls in par icular causes problems since they are
typically produced from flat strip which is then woun~ aroun~
the toroidal carcass causing some distortions of the strip
which may lead to side~7all blemishes in the finished tire.
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Other proposed methods of sidewall assembly include producing
an annular uncured sidewall in substantially its final shape in
a discrete annular sidewall mould which is brought into contact
with a shaped up carcass to fit the premoulded sidewall to the
carcass. The sidewall mould then forms part of the tire curing
mould. Such a method is proposed in British Patent GB21 34439Ao
However this method has the disadvantage that it is not
applicable to conventional tire building methods.
Accordingly there is provided an apparatus for the manufacture
of an annular uncured elastomeric component for a tire and
which comprises a disc-like mandrel on which an unvulcanised
elastomeric component can be formed, the mandrel comprising a
flexible support having a surface thereon to receive a strip of
unvulcanised elastomeric material, and a rigid carrier onto
I which the support i5 mounted, the carrier being adapted for
;i~ mounting on a turning head for rotation of the mandrel as the
strip is laid onto said receiving surfaceO
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Preferably the apparatus further provides a means for pxoducing
unvulcanised elastomeric strip, a turning head for rotating the
mandxel relative to the strip producing means so as to wind the
strip onto the mandrel.
The unvulcanised strip may be produced by an extruder and the
extrudate formed to its final shape by a calender before being
wound onto the surface.
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Conveniently the former may have a frustoconical outer surface
onto which the strip is wound and the mandrel is held at a
orientation
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such that the frustoconical suface is substantially hori~ontal
at the point of ap~lication of the strip to the mand~e1-
Also according to this invention there is provided a me~ho~ o~~nanufacture of an uncured elastomeric annular comIonent for a
tire wherein the component i~ formed directly onto a fle~ible
disc like mandrel by winding an unvulcanised elastomeric stri~
onto the mandrel, the mandrel with GOmponent in-situ is then
tr~nsfered to a second location at which the co.-nponent is
assembled to a tire, preferably without being removed from the
flexible Mandrel b~ore aasembly to the tire has occurred.
The inve~tion will be described by way of exam~le an~ with
re~erence to the accompanying drawings in which:
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- FIG 1 is a cro~ ction through a mandrel forming a ~art of
¦ the apparatus of the present invention
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FIG 2 in a schematic drawing illustrating a method of
manufacture of a tire component according to this invention.
FIG 3 1~ an elevation o~ an apparatus according to this
invention showing the mandrel in-situ
FIG 4 i~ an elevation of the apparatus of FIG 3 showing the
calender in-si~u.
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Now ~ith re~erence to Fig 1 of the accolnpanyin~ dra~/incJs, an
annular component for a tire, preferably atl ul;cured side~7all 11
for a radial carcass pneumatic tire, is pro~uced ol~ a mandrel 10
at one station ~nd is then transfered in situ on the ma~rel 10
to another station as a component in substantially its fi-nished
shape. The mandrel comprises an annular support 12, made
preferably from a polyure~hane elastomer, which is mounted on a
rigid coaxial transferable carrier 13~ The flexible su~ort 12
in its relaxed configuration has a frustoconic~l ou~er surface
14~on which the sidewall llt also in fr~stoconical form, is
laid.
I~ will be seen that the radially inner sur~ace o~ the carrier 13
has a conical seat 15 the~otland an annu7ar latching groove 16
whose f~nctions are associated with the mounting o~ the carrier
to an apparatus for the forming o~ the sidewall 11 and also for
the subsequen~ assembly of the sidewall to a tire at a seconcl
apparatus. There ls also at least one air passage 17 extending
through the flexible su~ort 12 from the conical surface 14 to
the radially outer cylindrical surface 18 of the c~rrier. This
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pa~sageway may be untilised for the applica;ion of vacuum to
.- hold the sidewall component in place, or for the application of
air to separate the sidewall component from the polyurethane support 12
The flexible support 12 is utilised in a later proces~ which
does not form part of the present invention, for the transfer
. of the sidewall 11 to a tororoida~ tire carcass.
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~3275~3
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Now with reference to FIG 2, the uncured sidewall 11 is formed
onto the mandrel 10 by spirally winding a strip 22 of uncured
elastomeric material onto the frustoconical surface 14 o the
mandrel~
The elastomeric sidewall material is processed by an extruder 23
and the extrudate 24 is fed to a conveyor 25 via a loop so as to
even out variations in speed batween the con~ey take-off and the
extruder out put. Th~ extrudate while still warm is fed to a pair
of calender rolls 26 which form part of a laying head 28 of the
type described in European Application 87630236, which was
published under number EP 0268544 on May 25, 1988. The calendered
strip 22 is then ~ed around an application roller 27, also on the
head 28, to lay he strip onto the mandrel.
The mandrel 10 and the laying head 2 are moved relatlve to each
other, preferably by rotation of the mandrel 10 about its axis
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whilst moving the laying head 28 radially of the mandrel to form
then an uncured sidewall comprising a plurality of turns of strip
on the mandrel in substantially its ~inished form.
The rotational speed of the mandrel is varlable to compensate for
the changing circum~erence of the mandrel surface as the strip is
wound radially inwardly or outwardly so as to maintain a constant
surface speed at the point of application of .the strip to th~
mandrel.
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With reference to FIG 3 and FIG 4 the extrudate strip 24 is passed
between the rollers 26a and 26b of the laying head 28 which is
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mounted on a main frame 29 of the apparatus. The laying head is
mounted on the frame 29 by means of struts (not shown) on which
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th head is moveable æo that its position can he altered as 1B deslred
to lay the calendered strip across the frustoconical surface 14 of the
mandrel 10. The laylng head may be moved by screw threaded struts and
the movement o~ khe head ls co-ordlnated wlth the speed of the calender
and the rotatlon of the mandrel so as to splrally wind an annular
s~dewall component 11 onto the surface of the mandrel, elther in
abutment or overlap as deslred. The relatlonship between th~ mandrel
rotatlon and the traverslng speed of the laying head is ~lso varlable so
that a deslred amount of overlap ~etween subsequent turns of the
extrudate can be achieved. This enables a range of dlfferent proflles
(cross sectlonal) to be made.
The mandrel 10 ls mounted on ~ turning head 31 for rotatlon about lts
a~ls. The turnlng head 31 1~ located at the upper end of a cylindrlcal
body 32 and ls caused to rotate thereln by a drlve belt or chain 33
connected between a pulley 35, on a shaft connected wlth the head 31 and
located at the lower end of ~he body 32, and a motor 34, preferably an
electrlcal motor. The motor, 3~, cyllndrical body 32, and mandrel 10
are all mounted on a ~ub-frame 36 which ln turn ls mounted by pivots ~7
to the maln frame 29 so tha~ the angle of orlentation of the cyllndrlcal
body 32 and hence the mandrel can be altered relatlve to the frame 29 by
operatlon of an actuator 3~.
As lllustrated ln FIG 3 and 4 the mandrel 10 is orlentated in the
desired position ~or recelving the c~lendered strlp 22, and is oriente~
wlth lts axls at an angle to the vertlcal so that lts frustoconlcal
outer surface 14 ls substantially horlzontal at the polnt of applicatlon
of the strlp 22 to the mandrel. The calendered strlp ls fed onto the
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mandrel vla an application roller 27 which may exert a llyht appllcatlon
load t500 gms) onto the strip as it is fed onto the ~urface of th~
mandrel.
The applicatlon roller 27 is mounted on an arm 41 pivoted to the laylng
head 28 which ls moveable by and actuator 42 to llft the roller 27 off
the mandrel or exert the appllcatlon load.
The laying head 28 wlll move radially across the mandrel surface 14 as
the strip 1~ lal~ and on completion of the component the strip ls cut by
a cutter 43 (see FIG 2) which ls mounted on the arm 41.
A~ter com~letlon of tha formlny of the sidewall 11, the mandrel 10 is
reorlentated so that lts a~ls ls vertlcal and the mandrel is removed
from the turniny head 31 with the component ln sltu.
; The mandrel and component are then taken to another machlne statlon ~or
assem~ly to a torolded tire carcass. Thls latter operation is descrlbed
h in our copending appli~atlon filed on the same day a~ the present
applicatlon.
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